Stocks with large increases in call (put) implied volatilities over the previous month tend to have high (low) future returns. Sorting stocks ranked into decile portfolios by past call implied volatilities produces spreads in average returns of approximately 1% per month, and the return differences persist up to six months. The cross section of stock returns also predicts option-implied volatilities, with stocks with high past returns tending to have call and put option contracts that exhibit increases in implied volatility over the next month, but with decreasing realized volatility. These predictability patterns are consistent with rational models of informed trading.
Observed changes in the implied volatilities of options can be considered a good measure of news arrival in the option market. Additionally, if some informed investors trade in option markets before trading in the underlying stock, option prices might predict future stock price movements. Indeed, this study finds that changes in option implied volatilities are correlated with subsequent stock returns.
Portfolio returns are sorted based on changes in option implied volatilities. Panel A in the table below shows decile portfolios of stocks sorted by changes in implied volatility of call options, or ΔCVOL (Panel B based on ΔPVOL is omitted here).
Portfolio 1 (Low ΔCVOL) contains stocks with the lowest changes in call option implied volatilities in the previous month;
Portfolio 10 (High ΔCVOL) includes stocks with the highest changes in call option implied volatilities in the previous month.
The results show that a long/short strategy going long (short) stocks with call options with the highest (lowest) changes in implied volatilities earns returns of approximately 1% per month. Call option volatility appears to be a good predictor for future stock returns. Also, this predictability is persistent, lasting up to 6 months (see table V).
The results are hypothetical results and are NOT an indicator of future results and do NOT represent returns that any investor actually attained. Indexes are unmanaged, do not reflect management or trading fees, and one cannot invest directly in an index. Additional information regarding the construction of these results is available upon request.
Intriguingly, the paper also explores using both call and put option volatility, potentially to greater effect.
After serving as a Captain in the United States Marine Corps, Dr. Gray earned an MBA and a PhD in finance from the University of Chicago where he studied under Nobel Prize Winner Eugene Fama. Next, Wes took an academic job in his wife’s hometown of Philadelphia and worked as a finance professor at Drexel University. Dr. Gray’s interest in bridging the research gap between academia and industry led him to found Alpha Architect, an asset management firm dedicated to an impact mission of empowering investors through education. He is a contributor to multiple industry publications and regularly speaks to professional investor groups across the country. Wes has published multiple academic papers and four books, including Embedded (Naval Institute Press, 2009), Quantitative Value (Wiley, 2012), DIY Financial Advisor (Wiley, 2015), and Quantitative Momentum (Wiley, 2016).
Dr. Gray currently resides in Palmas Del Mar Puerto Rico with his wife and three children. He recently finished the Leadville 100 ultramarathon race and promises to make better life decisions in the future.
Performance figures contained herein are hypothetical, unaudited and prepared by Alpha Architect, LLC; hypothetical results are intended for illustrative purposes only. Past performance is not indicative of future results, which may vary. There is a risk of substantial loss associated with trading stocks, commodities, futures, options and other financial instruments. Full disclosures here.